Mitt Romney and President Obama talk after the first presidential debate at the University of Denver. / Charlie Neibergall, AP

by USA TODAY

by USA TODAY

There's never been a 269-269 tie in the Electoral College, and it's not likely this time. But in an election nearly everyone says is going to be close, it is at least mathematically and politically possible to construct one.

One scenario: President Obama wins the states now solidly or leaning Democratic, including Michigan, Pennsylvania and New Mexico, while Mitt Romney wins the states now solidly or leaning Republican, including North Carolina.

The 12th Amendment of the Constitution specifies what would happen next. If no candidate wins a majority of the Electoral College - that's happened just once, in the 1824 election - the presidential contest would be thrown to the House of Representatives. Each state delegation would get a single vote, determined by the state's new congressional delegation.

Likely winner: Romney, since 33 state delegations are now controlled by Republicans.

That election wouldn't take place until after the Electoral College votes officially are counted before a joint meeting of the House and Senate Jan. 7.

The Senate would choose the new vice president from the two top finishers in the Electoral College. That election is harder to predict, given that Republicans hope to gain a majority in the new Senate. Democrats and their independent allies now control the Senate, 53-47.

One even-more-distant prospect: If the Senate deadlocks 50-50 on a new vice president, the person breaking a tie would be Vice President Biden - who could, of course, vote for himself.